92 lines
3.7 KiB
JavaScript
92 lines
3.7 KiB
JavaScript
/*
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MIT License
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Copyright (c) 2018 Luke Park
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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const crypto = require("crypto");
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const ALGORITHM_NAME = "aes-128-gcm";
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const ALGORITHM_NONCE_SIZE = 12;
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const ALGORITHM_TAG_SIZE = 16;
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const ALGORITHM_KEY_SIZE = 16;
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const PBKDF2_NAME = "sha256";
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const PBKDF2_SALT_SIZE = 16;
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const PBKDF2_ITERATIONS = 32767;
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export class SCEE {
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encryptString(plaintext, password) {
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// Generate a 128-bit salt using a CSPRNG.
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let salt = crypto.randomBytes(PBKDF2_SALT_SIZE);
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// Derive a key using PBKDF2.
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let key = crypto.pbkdf2Sync(new Buffer(password, "utf8"), salt, PBKDF2_ITERATIONS, ALGORITHM_KEY_SIZE, PBKDF2_NAME);
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// Encrypt and prepend salt.
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let ciphertextAndNonceAndSalt = Buffer.concat([ salt, this.encrypt(new Buffer(plaintext, "utf8"), key) ]);
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// Return as base64 string.
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return ciphertextAndNonceAndSalt.toString("base64");
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}
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decryptString(base64CiphertextAndNonceAndSalt, password) {
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// Decode the base64.
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let ciphertextAndNonceAndSalt = new Buffer(base64CiphertextAndNonceAndSalt, "base64");
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// Create buffers of salt and ciphertextAndNonce.
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let salt = ciphertextAndNonceAndSalt.slice(0, PBKDF2_SALT_SIZE);
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let ciphertextAndNonce = ciphertextAndNonceAndSalt.slice(PBKDF2_SALT_SIZE);
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// Derive the key using PBKDF2.
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let key = crypto.pbkdf2Sync(new Buffer(password, "utf8"), salt, PBKDF2_ITERATIONS, ALGORITHM_KEY_SIZE, PBKDF2_NAME);
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// Decrypt and return result.
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return this.decrypt(ciphertextAndNonce, key).toString("utf8");
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}
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encrypt(plaintext, key) {
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// Generate a 96-bit nonce using a CSPRNG.
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let nonce = crypto.randomBytes(ALGORITHM_NONCE_SIZE);
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// Create the cipher instance.
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let cipher = crypto.createCipheriv(ALGORITHM_NAME, key, nonce);
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// Encrypt and prepend nonce.
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let ciphertext = Buffer.concat([ cipher.update(plaintext), cipher.final() ]);
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return Buffer.concat([ nonce, ciphertext, cipher.getAuthTag() ]);
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}
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decrypt(ciphertextAndNonce, key) {
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// Create buffers of nonce, ciphertext and tag.
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let nonce = ciphertextAndNonce.slice(0, ALGORITHM_NONCE_SIZE);
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let ciphertext = ciphertextAndNonce.slice(ALGORITHM_NONCE_SIZE, ciphertextAndNonce.length - ALGORITHM_TAG_SIZE);
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let tag = ciphertextAndNonce.slice(ciphertext.length + ALGORITHM_NONCE_SIZE);
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// Create the cipher instance.
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let cipher = crypto.createDecipheriv(ALGORITHM_NAME, key, nonce);
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// Decrypt and return result.
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cipher.setAuthTag(tag);
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return Buffer.concat([ cipher.update(ciphertext), cipher.final() ]);
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}
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}
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